Water Heater only Luke Warm

My water heater is only putting out luke-warm water. I put an OHM reader to the upper element and lower element at 1k OHM and both needles moved to infinity so I'm assuming both elements are ok. I just turned the heater on and the upper element is currently on but the lower element is not.

I should note that this happened right after I replaced my well pump. I could hear a dripping when I emptied the pressue tank and couldn't identify where it was coming from. Waht I think might have happened is that due to no pressure in the system, the hot water tank could have lost a bit of water. After I turned everything back on, the hot water got REALLY hot - hotter than it's ever been - then went luke-warm. Sounds like the upper element burning out, right? So why is the multi-meter still showing movement. Maybe it's the thermostat?

Check thermostats for round red buttons.. these are manual reset high temp limit controls that pop at around 170 deg or so.

Just for your info,, as most water heaters I've seen, only one element is active at any time.. the top thermostat is a 3 way switch.. when its satisfied, it turns off and send power to the lower thermostat. When the lower thermostat is satisfied, it turns off too but still has power available. Since thermal currents rise, as the heater cools off, the bottom becomes cold first.

Ok, turns out that big magical reset button I THOUGHT I pushed... I didn't. Pushed it, water came back on.

Fast forward 4 hours, I measure hte temperature... 165 degrees Faranheit. Almost peeled the flesh right off my hands (but fantastic to clean dishes with). Thermostat is set to 130. Is that the problem now? COuld the thermostat blow because the water ran empty?

Ok, turns out that big magical reset button I THOUGHT I pushed... I didn't. Pushed it, water came back on.

Fast forward 4 hours, I measure hte temperature... 165 degrees Faranheit. Almost peeled the flesh right off my hands (but fantastic to clean dishes with). Thermostat is set to 130. Is that the problem now? COuld the thermostat blow because the water ran empty?

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Well this is unusual. It sounds to me like the contacts in your thermostat are frozen closed.. Either that, or the thermostat is not making contact with the tank.

Check to make sure the thermostat is making solid contact with the steel water tank and that it has insulation surrounding it.. A water heater thermostat that says it should be at 130 should ABSOLUTELY NOT let the water get to 160+.. that's a malfunction. Max temps on most water heater thermostats that I have seen are about 145 or so.

Well this is unusual. It sounds to me like the contacts in your thermostat are frozen closed.. Either that, or the thermostat is not making contact with the tank.

Check to make sure the thermostat is making solid contact with the steel water tank and that it has insulation surrounding it.. A water heater thermostat that says it should be at 130 should ABSOLUTELY NOT let the water get to 160+.. that's a malfunction. Max temps on most water heater thermostats that I have seen are about 145 or so.

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Should I just go ahead and replace it? The unit actually looks quite old.

When I tested the element the ohm reader read open. I just replaced the thermometer and so far so good. Temperature is where it should be. Is it normal for the element on top to be on constantly? It's a 240 v element when I change the temp and force the element on it reads 240 v when thermometer shuts the elemennt off it reads around 120v.

When I tested the element the ohm reader read open. I just replaced the thermometer and so far so good. Temperature is where it should be. Is it normal for the element on top to be on constantly? It's a 240 v element when I change the temp and force the element on it reads 240 v when thermometer shuts the elemennt off it reads around 120v.

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If you are reading across the element terminals then that is not normal. Are you reading the voltage to ground ?

It's not getting too hot, that's the odd thing. Staying right around 130.

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That is a good thing.

It sounds like your elements may be hooked in series if you have 120 on them. Or maybe it is a 120V unit. That is why I asked for a model #. But why they had 240 on them don't make sense. Unless you were working in your breaker panel wiring your new water pump. If the new thermostat is wired wrong, that could cause 120, but you would need to be swapping wires. Also some units may do that for efficiency. Model maters.

I am clueless at this point. But still suspect the top element if no wiring was changed. Because of the fact that it may have been on with no water to cool it.

Just make sure your Pop Off Valve is good and has a place for the water to go.

Sometimes it is best to download the manual for what you are working on, Before you start working on it. Then You can understand how it works, and be Safe working on it.

Water Heaters are really fairly simple if you know how they work.

For safety reasons if you do not know how they work then you should not work on it.

Read your Meter manual also, so you know what you are reading and measuring.

If I am wrong then please tell me, in a PM if needed.

Terry's site has good info, But He and Myself like for everyone to be safe when working on a DIY project.

It sounds like your elements may be hooked in series if you have 120 on them. Or maybe it is a 120V unit. That is why I asked for a model #. But why they had 240 on them don't make sense. Unless you were working in your breaker panel wiring your new water pump. If the new thermostat is wired wrong, that could cause 120, but you would need to be swapping wires. Also some units may do that for efficiency. Model maters.

I am clueless at this point. But still suspect the top element if no wiring was changed. Because of the fact that it may have been on with no water to cool it.

Just make sure your Pop Off Valve is good and has a place for the water to go.

Sometimes it is best to download the manual for what you are working on, Before you start working on it. Then You can understand how it works, and be Safe working on it.

Water Heaters are really fairly simple if you know how they work.

For safety reasons if you do not know how they work then you should not work on it.

Read your Meter manual also, so you know what you are reading and measuring.

If I am wrong then please tell me, in a PM if needed.

Terry's site has good info, But He and Myself like for everyone to be safe when working on a DIY project.

Good Luck.

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I'm really paranoid that I wired something wrong now. The model is a Rudd ET-40.

FWIW, ALWAYS go clockwise around a screw with a wire, and it's never a good idea to try to put two solid wires underneath one screw terminal. I don't know enough about electric WH to tell if it's wired properly.